Currently ore generation inside of grimstone uses normal ores, causing them to stick out. However, a fix for this is underway: https://twitter.com/henrikkniberg/status/1362095363314876418
However, ores are still capable of generating inside of patches of granite and diorite, which they very clearly stick out of and look rather unsightly as a result.
This could be fixed by introducing variants of ores for these stones as well (like what was done to fix MC-7449, MC-55228 and MC-126564), or just preventing them from spawning inside of these entirely.
As andesite is extremely similar in color to stone, it may or may not be worth adding variant ores for these
This is a feature request.